1. Field
Embodiments relate to a solder paste as an admixture of solder powder and a flux for soldering.
2. Background
Reflow soldering is used for internal bonding of electronic components in consideration of fine bonding parts. A solder paste used in reflow soldering is an admixture of solder powder and a flux for soldering.
To prevent environmental pollution, lead-free solder (referred to as “Pb-free solder”) has widely been used in internal bonding of electronic components. Pb-free solder refers to solder powder that does not include Pb and combines two or more elements of Sn, Ag, Sb, Cu, Zn, Bi, Ni, Cr, Fe, P, Ge, Ga, and the like with each other.
In addition, Sn—Ag based alloys in which Sn, Ag, and Cu are mixed with one another has widely been used as Pb-free solder. Since soldering temperature is within a range of about 240° C.˜250° C. when using Sn—Ag based alloys, Pb-free solder requires a high solidus temperature of at least 250° C.